Sharp MZ-5500 - Page 36

Programming example (for the circuit example- ):
' CSEG
ORG 100H
CLI
XOR AX, AX Saving and setting
MOV DS, AX interrupt address
MOV
BX, 100H+4*13
MOV
AX,
[BX]
MOV CS=INTADR, AX
MOV
AX, OFFSET INT25
1
MOV
[BX], AX
ADD BX, 2
MOV AX,
[BX]
MOV
CS: INTADR+2, AX
MOV AX, CS
MOV
[BX], AX
PUSH
CS
J 8080 model
POp "
DS
IN
Al., 42H
]
Clear the .mask register
AND AL, ODFH
OUT
42H, AL
STI
1
I
Interrupt enabled
INTADR DB 0, 0, 0, 0
INT25:
PUSH
AX Interrogate interrupt
1
1
PUSH
DX
MOV DX, lCOH
IN
AX, DX
AND
AX, 1
i'
JNZ INTA
POP DX
POP
AX
JMPF
CS=INTADR
J
To next level interrupt
routlne
INTA:
OUT
DX, AX
J
Interrupt acknowledge
Interrupt processing
MOV
AL, 20H
EOI genera ted and return
l
OUT
40H, AL .
OUT
30H, AL
POP
DX
POP
AX
IRET
3'3